1. Field of the Invention
The present invention relates to a head carriage support mechanism and, in particular, to a head carriage support mechanism to be provided with a magnetic head which is used especially in a magnetic recording or reproducing apparatus in an electronic camera system or the like to magnetically record still image information or the like into a magnetic disc or reproduce such still image information from the magnetic disc.
2. Description of the Related Art
Recently, there has been developed an attractive electronic camera system wherein an image pickup device, such as a solid image pickup element, an image pickup tube or the like, is combined with a recording device employing, as a recording medium, an inexpensive magnetic disc having a comparatively higher memory capacity to photograph an object electronically and record it into the rotating magnetic disc and to reproduce an image by a television system or a printer separatly provided.
The magnetic disc used in the above-mentioned camera system has a diameter of the order of 50 mm. And, in the above-mentioned system, a head carriage provided with a magnetic head can be moved in the radial direction of the magnetic disc to thereby magnetically record or reproduce still image information into or from the magnetic disc for each of tracks provided on the magnetic disc.
Referring now to FIG. 21, there is shown a sectional view of a magnetic head feeding device according to the above-mentioned prior art. In this figure, a lead screw 10 has a threaded portion 10A in the central portion thereof and, on either side of the threaded portion 10A, there are mounted oilless metal sections 12 and 14, respectively. A head carriage 16 includes a needle 18 biased by a tension spring 18A to engage with the threaded portion 10A and also has slidable portions 16A and 16B which can slide over the above-mentioned oilless metals sections 12 and 14, respectively. The slidable portions 16A and 16B are formed of resin or the like, respectively. In addition, to the above head carriage, there is mounted a magnetic head which is not shown.
The above-mentioned lead screw 10 is mounted through ball bearings 20 and 22 to the main body 24 of the magnetic recording or reproducing apparatus and is further connected to a stepping motor 28 through a coupling 26. Therefore, if the stepping motor 28 is rotated a predetermined amount, the lead screw 10 is also rotated on the other hand, on the side of the head carriage that does not rotate the needle 18 thereof is guided by the threaded portion 10A of the lead screw 10 so that the head carriage 16 is moved a predetermined amount in the axial direction of the lead screw 10 and, at the same time, the magnetic head is also moved in the radial direction of the magnetic disc.
However, due to the fact that the above-mentioned prior art head carriage 16 is adapted to slide in a surface contact manner, the oilless metal sections 12 and 13 or similar means on the shafts at both ends of the threaded portion 10A of the lead screw 10. Also, since the lead screw is supported by means of the ball bearings, there is a problem in the prior art head carriage that the structure is complicated in structure and is difficult to assemble.
Further, unlike a magnetic disc used in an ordinary magnetic recording/reproducing apparatus, a higher density of still or moving image information is recorded in the magnetic disc used in the electronic camera or the like, and also it is rotating at a higher speed. For this reason, the magnetic head, which must be in contact to record into or reproduce from such a magnetic disc, requires accurate adjustment of position with respect to the magentic disc.
In view of the above-mentioned circumstances, the magnetic head used to record or reproduce the still image information and the like in the electronic camera or the like must be adjusted in the following five respects: namely, (1) an amount of projection or extension, (2) an angle of inclination, (3) a shift in center alignment, (4) a shift in azimuth, and (5) a tilt. The above-mentioned five types of adjustments will be discussed below sequentially in connection with FIGS. 22 through 24.
In FIG. 22, 32 designates a magnetic disc, 1 a magnetic head to record into or reproduce from the magnetic disc, and 6 a regulation plate disposed at a position opposed to the magnetic head 1 with the magnetic disc 32 disposed therebetween to locate the magnetic disc 32 along the magnetic head 1. The magnetic head 1 requires a predetermined range of extension amount Ea with respect to the magnetic disc 32. For better recording and reproduction as well as in order to prevent wear in the magnetic head and recording medium, a fine adjustment must be carried out.
In order to be able to obtain an excellent reproduction image even when the same recording medium is loaded into different reproducers, and further when a recording head and a reproducing head, which are provided separately from each other, are employed, as in a case wherein a recorder and a reproducer are constructed separately from each other, the angle of inclination .theta.a of the magnetic head as shown in FIG. 22, the center alignment shift amount Eb of the magnetic head 1 with respect to the center of the magnetic disc 32 and the azimuth shift .theta.b of the magnetic head 1 as shown in FIG. 23, and the tilt angle .theta.c of the magnetic head 1 with respect to the magnetic disc 32, as shown in FIG. 24, must be within a predetermined range which is compatible.
In the prior art, to mount the magetic head, the magnetic head is set at a proper position, the head carriage is moved in the feeding direction of the magnetic head with respect to the magnetic head, the contact surface of an L-shaped head mounting plate previously provided in the head carriage is made to approach the contact surface of the magnetic head, and then adhesives are poured in between the two contact surfaces.
However, in the above-mentioned magnetic head mounting method, since the L-shaped head mount plate and the magnetic head are bonded to each other in a surface-to-surface contact manner, there is a possibility that the position of the magnetic head may be out of order by the influences due to temperature changes or curing contraction when the thicknesses of the adhesive layer are not even or are 100.mu. or more.
If such position disorder is corrected by mechanically deforming the L-shaped head mount plate, for example, to adjust the azimuth shift of the magnetic head, then there arises another problem that the remaining adjustments of the magnetic head may be out of order.